Memory elements associated with integrated circuit devices may comprise either volatile or non-volatile memory elements. Volatile memory elements will not retain data stored in the memory elements when power is removed from the memory elements. However, there may be some circumstances where it may be necessary to retain data after power is removed. Accordingly, non-volatile memory elements, which retain stored data, may be implemented in an integrated circuit device. Implementing non-volatile memory may have a number of disadvantages, including higher cost and reduced performance of the entire integrated circuit device due to the additional manufacturing steps required for non-volatile memory compared to volatile memory elements.
Data may be retained in volatile memory by implementing a source of back-up power, such as a back-up battery, which is applied to the volatile memory after the main power is removed. The source of back-up power is provided to maintain power in the volatile memory. However, such a source of back-up power may not only be expensive to implement, but may also unnecessarily occupy space in a device or system implementing the volatile memory. Further, in applications of non-volatile memory related to the security of data, an external power supply or external memory may be considered too insecure for the application. While it may be beneficial to retain data in the memory, it may be cost or resource prohibitive to implement non-volatile memory or to provide a back-up source of power in some applications.
Further, it may be necessary to retain data for only a short period of time in certain instances. Accordingly, implementing non-volatile memory may not be essential to the active operation of the device, and the non-volatile memory may only be used in limited applications or during limited times. However, such non-volatile memory may provide an important, although limited, function necessary in the overall operation of the device.